The present invention relates to, for example, a display module which can be adopted to a liquid crystal display module.
A TFT (Thin Film Transistor) liquid crystal display module has been known as a conventional display module. Referring to FIG. 13, its structure will be explained. Here, a module means an independent unit which meets requirements for constituting a large system such as a TV set or a personal computer, just by combining these units.
As shown in FIG. 13, a conventional TFT liquid crystal module 101 is composed of a controller 102, a gate electrode driving circuit 103, a source electrode driving circuit 104, and a liquid crystal panel 105. The controller 102 is equipped with a liquid crystal driving power source circuit 106. The gate electrode driving circuit 103 has a gate driver group including gate drivers GD1 through GDm. The source electrode driving circuit 104 has a source driver group including source drivers SD1 through SDn.
The controller 102 controls the generation of scanning pulses in the gate electrode driving circuit 103, and the timing of N-bit display data signals and driving control signals in the source electrode driving circuit 104. The controller 102 performs the timing control based on synchronization signals (vertical and horizontal synchronization signals) supplied from an external device (host system).
The liquid crystal driving power source circuit 106 in the controller 102 receives power from an external source, and supplies power to a common electrode for the gate electrode driving circuit 103, the source electrode driving circuit 104, and the liquid crystal panel 105.
The gate drivers GD1 through GDm in the gate electrode driving circuit 103 are high power output drivers driving gate bus lines Bgs shown in FIG. 6, provided in the liquid crystal panel 105 in a horizontal direction. Each of the gate drivers GD1 through GDm is composed of a LSI chip. Each LSI chip has a TCP (Tape Carrier Package) form so as to connect its input/output terminals to electrodes of other components. That is, each of the gate drivers GD1 through GDm is installed on a film called a tape carrier in which copper foil wiring is laid out at minute intervals on an insulation film. Each of the gate drivers GD1 through GDm is sealed with a resin provided for fixing the LSI chip and for protecting the LSI chip from moisture.
The source drivers SD1 through SDn of the source electrode driving circuit 104 are high power output drivers driving source bus lines Bs""s shown in FIG. 6, provided in the liquid crystal panel 105 in a vertical direction. Each of the source drivers SD1 through SDn also has a TCP (Tape Carrier Package) form so as to connect its input/output terminals of the LSI chip to electrodes of other components.
Next, the following description will describe a specific installation structure of the conventional liquid crystal display module. The liquid crystal display module shown in FIG. 14 has cascaded two gate drivers GD1 and GD2, and cascaded eight source drivers SD1 through SD8. Each of these source drivers SD1 through SD8 and the gate drivers GD1 and GD2 is composed of a LSI chip.
The gate drivers GD1, GD2 are provided on a common wiring substrate 111 which is common to these gate drivers. Likewise, the source drivers SD1 through SD8 are provided on a common wiring substrate 112 which is common to these source drivers. These common wiring substrates 111 and 112 supply common signals and power to the gate drivers GD1, GD2 and the source driver SD1 through SD8. The controller 102 is provided on a controller substrate 113, which is a substrate different from the common wiring substrates 111 and 112. Incidentally, a material with reference numeral 114 is a TCP type film having wiring, and a material with reference numeral 115 is a flexible substrate for connecting the wires of the controller substrate 113 with the wires of the common wiring substrates 111 and 112.
Wires on the TCP type film 114 and ITO (Indium Tin Oxide) wires on the liquid crystal panel 105 are connected by thermocompression bonding at a fringe section 105a of the liquid crystal panel 105, via an ACF (Anisotropic Conductive Film). Meanwhile, the electrical connections between the wires on the TCP type film 114 and the common wiring substrates 111 and 112, and between the controller substrate 113 and the common wiring substrates 111 and 112 are established by soldering or by the ACF method. The common wiring substrates 111 and 112 and the controller substrate 113 are made of, for example, multi-layer glass epoxy substrates.
Next, FIG. 15 shows another liquid crystal display module. In this liquid crystal display module, the common wiring substrates 111 and 112 are eliminated by using internal wires in LSI chips. This liquid crystal display module is disclosed in Japanese Unexamined Patent Publication No. 6-3684/1994 (Nishioka 6-3684/1994, published on Jan. 14, 1994), applied by the same applicant of the present invention. In the liquid crystal display module, the gate drivers GD1, GD2 and the source drivers SD1 through SD8 are respectively installed on different TCP type films 114. The electrical connection between the adjacent TCP type films 114 is established by overlapping the ends of the wires of the TCP type films 114.
Also in this example, the controller 102 is provided on an independent controller substrate 116, which is made of glass, an epoxy substrate, or a flexible substrate. The controller 102 is connected to the gate drivers GDs and the source drivers SDs via a flexible substrate, by means of the ACF method and soldering.
Another example for electrically connecting the adjacent TCP type films 114 is disclosed in Japanese Unexamined Patent Publication No. 2000-242240/2000 (Tamai et al. 2000-242240, published on Sep. 8, 2000), applied by the same applicant of the present invention. In this example, the foregoing connection is established using a separately provided film substrate having wiring only, or ITO wires for connection provided on the liquid crystal panel 105, by an ACF method or soldering.
However, recently, a lower priced, and downsized liquid crystal display module has been increasingly demanded in the market, which requires further consideration. Thus, in order to reduce the total cost of a liquid crystal display module and achieve downsizing, a maximized reduction in weight, the number of parts, and wires required in a display driving device including a controller which especially performs plenty of signal transmission, has been strongly desired.
The object of the present invention is provide a display module which achieves a small and light-weight structure by reducing the number of parts, and achieves cost reduction.
To obtain the foregoing object, a display module in accordance with the present invention includes:
a display device driven by a driving signal in a column direction and a driving signal in a row direction;
a first driving device for supplying the driving signal in a column direction;
a second driving device for supplying the driving signal in a row direction;
a first wiring substrate for mounting thereon the first driving device;
a second wiring substrate for mounting thereon the second driving device; and
a control device for controlling the first and the second driving devices, which is installed on the first or the second wiring substrate together with the first or the second driving device.
According to the foregoing structure, the control device for controlling the first and the second driving devices is installed on the first or the second wiring substrate together with the first or the second driving device. Therefore, the structure eliminates the need for a wiring substrate for installing the control device only, achieving the reduction in the number of parts and cost reduction. Further, the structure does not require space for providing the wiring substrate exclusive for installing the control device, achieving miniaturization.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.